1992 ex500. Ran out of gas about a week ago. Closest gas station (7-11) only had 87octane. So I put that in it. Calls for 91. Now bike won't idle. Have to ride around with choke on to keep the rpm's up so that the bike won't shut off... if rpms are 2000 or lower, bike stalls. Figured i'd run it dry, fill it back up with 91 and i'd be good to go... NOPE. It used to idle nicely at around 1200rpm. Tried an octane booster... didn't help. Don't know why I would have to seeing as how it was running fine previously but do you guys think I have to adjust the air/fuel ratio?? Any thoughts are greatly appreciated. Or any questions if I left out any info... oh and other than idle, once I'm above 2000rpm, bike runs fine. Doesn't run rough at all and performs great. But once I pull up to that stop light, shuts off. And its NOT the butterfly valve adjustment.